Just seven Republicans appeared on the main debate stage Thursday, the smallest group yet, but the exclusivity did little to sort out the crowded field.

Here's what was notable:

The Trump-Cruz feud isn't going anywhere

The fraying bromance between Trump and Cruz spilled into the open over not just the billionaire's suggestion that Cruz may not qualify for the presidency because he was born in Canada, but also over Cruz's accusation that Trump represents "New York values."

Rubio tries to be angrier

Rubio's greatest asset has been his optimistic message, rooted in an inspirational family story as the son of Cuban immigrants who rose to become a senator.

But as Rubio's candidacy has, like everyone else's, been stuck in Trump's shadow, his tone has sharpened.

Three debate moments people are talking about that have nothing to do with Donald Trump

Donald Trump certainly knows how to spark a conversation. Indeed, two of the top-Tweeted moments from Thursday's debate were about him. But the lesser-known candidates generated plenty of commentary themselves. Here's what the Internet was talking about:

Ben Carson hates the comments section

Ben Carson spoke the least during the debate, according to an NPR tally. Still, his disbelief at the uncivil discussions in online comments sections didn’t go unnoticed.

“You go to the Internet, you start reading an article and you go to the comments section," Carson said during a brief discourse on the combative nature of some people, a contrast to his own soft-spoken bearing. “You cannot go five comments down before people are calling all manner of names."

Twitter responded with advice:

An absent Rand Paul gets a rallying cry

Rand Paul declined to join the so-called undercard debate. Instead, he opted to hold his own town hall on Twitter.

Though he was gone from the stage, his name didn’t go unsaid.

“We want Rand!” rang through the crowd midway through the main debate. Simultaneously, #RandRally popped up on Twitter.

Lindsey Graham gets love from the cameras

Graham may no longer be running for president, but he hasn’t been forgotten. Graham, the home-state senator in front of the South Carolina crowd, was a delight in earlier undercard debates, bringing to bear a lighthearted wit that belied his dark outlook on national security.

On Thursday night, he was in the audience for the debate, and the cameras panned to him, causing some to pine for his presence on the debate stage again:

Which GOP candidates would ban Muslims?

Donald Trump's repeated calls to ban all Muslims from entering the United States has provoked lots of controversy -- and has corresponded with a boost in his ratings.

Tonight's debate moderators asked Trump's competitors whether they agree with his proposal for a ban. Here are their responses.

Jeb Bush: No. "All Muslims ... seriously? Are we going to ban Muslims from India? Of course not. What we need is a plan to destroy ISIS."

Ted Cruz: Did not answer the question. But he did call for a ban on refugees coming from countries, such as Iraq and Syria, where ISIS controls significant territory.

John Kasich: Did not answer the question. But he did reiterate previous calls for a pause on Syrian refugees.

Chris Christie: No. "You can't just ban all Muslims. you have to ban ... the people who are trying to hurt us. We don't have to ban everybody, just the people who are trying to harm us."

Marco Rubio: Did not answer the question. "If we do not know who you are and we do not know why are you coming you will not get in to the United States of America."

Ben Carson: Did not answer the question. Said more needs to be done in the Middle East to stop war refugees from coming here.

8:05 P.M.

A brief interruption from Rand Paul supporters

7:54 P.M.

What exactly are #NewYorkValues? The Internet explains

Ted Cruz dismissed Donald Trump's conservative beliefs this week as "New York values" as the Republican front-runners escalate their attacks on each other. Not surprisingly, the moderators of Thursday night's debate asked Cruz to define the phrase.

It didn't take long for debate-watchers to interject with their own #NewYorkValues:

7:41 P.M.

We don't need a weak person as president of the United States. That's what we'd get if it was Jeb.

Chris Christie: We need a no-fly zone over Syria

(Rainier Ehrhardt /AP)

As Syria endures the fifth year of a civil war that has displaced millions of people, many Republican presidential hopefuls are pushing for the United States to implement a no-fly zone over the country to help protect Syrians trying to flee.

Former Florida Gov. Jeb Bush, Sen. Marco Rubio of Florida, New Jersey Gov. Chris Christie and retired neurosurgeon Ben Carson all support a no-fly zone in Syria. They argue that it would prevent civilian casualties and would be a show of force toward Russian President Vladimir Putin, whose military has carried out airstrikes on behalf of Syrian President Bashar Assad.

"We’re not going to have peace in Syria unless we have a no-fly zone," Christie said Thursday.

President Obama has resisted deeper U.S. engagement in the region, saying that he doesn’t want to get involved in another protracted conflict like the Iraq war and calling on regional allies to partner in the fight against Islamic State.

His policy of limited intervention while the militant group has capitalized on the chaos in Syria to seize large parts of the country and established strongholds in neighboring Iraq has hurt the U.S., Republicans said.

Here's why Trump and Cruz are going after each other, finally

After months of studiously avoiding criticizing Donald Trump, Sen. Ted Cruz lashed out at the billionaire in Thursday’s Republican debate, pointing to past liberal statements the front-runner has made.

Cruz reiterated a criticism he raised this week, that Trump had “New York values.”

“Everyone understands the values in New York City are socially liberal, are pro-abortion, are pro-gay marriage, focus around money and the media,” Cruz said, pointing to an interview that Trump did several years ago where he declared himself “very pro-choice.” “He explained, look, I’m from New York.... Those aren’t Iowa values but that’s what we believe in New York.”

“There are not a lot of conservatives coming out of Manhattan,” Cruz concluded. (That was a dig at Trump claiming that not many evangelicals come from Cuba – Cruz is evangelical and of Cuban descent).

Trump responded by recalling the days after the Sept. 11 attacks.

“The people in New York fought and fought and fought, and we saw more death. And even the smell of death … it was with us for months,” Trump said. “We rebuilt downtown Manhattan and everybody in the world watched, and everybody in the world loved New York and loved New Yorkers. And I have to tell you, that was a very insulting statement that Ted made.”

Trump and Cruz had been congenial on the campaign trail, avoiding attacking each other for months. That changed in recent weeks as the two became locked in a tight battle for the lead in Iowa, which in less than three weeks holds the first presidential nominating contest.

Trump went after Cruz first, questioning his faith, his Canadian birth, his temperament as a senator and his policies on ethanol and immigration. Cruz initially avoided hitting back, mindful that other candidates who did so have fared poorly, and hoping to keep from alienating Trump’s backers in case they ultimately decide not to vote for him or if Trump drops out.

That changed this week, when Cruz blistered Trump for having “New York values” and ties to Democrats, and mocked Trump’s foreign policy knowledge.

Presidential hopefuls Donald Trump and Rand Paul have gained more Twitter followers than other candidates since the start of Thursday's Republican debate.

Twitter's government and elections team tallied up the numbers comparing candidates on both sides of the aisle. Trump is one of seven participants on the main debate stage. Paul, on the other hand, declined Fox Business Network's invitation to participate in the undercard debate and opted to hold a Twitter "town hall" instead.

Is Bernie Sanders electable? One Republican sides with Hillary Clinton

(Joe Raedle / Getty Images)

On the campaign trail, Hillary Clinton has been telling voters that she, not Bernie Sanders, is the most electable Democrat out there.

And at the Republican debate in South Carolina on Thursday, she got some unlikely help making that argument from Ohio Gov. John Kasich.

Asked about the primary battle between Clinton and Sanders, Kasich chuckled.

“We’re going to win every state if Bernie Sanders is the nominee,” he said. “I know Bernie, and I can promise you he’s not going to be president of the United States.”

It’s similar to the warnings Clinton has been making. In Iowa last week, she asked voters to “think hard about the people who are presenting themselves to you, their experience, their qualifications, their positions.”

Then, in an oblique reference to Sanders, the Vermont senator whose democratic socialist beliefs could make him less viable in a general election, Clinton asked voters to consider candidates’ “electability, and how we make sure we have a Democrat going back to the White House.”

7:11 P.M.

Here's what President Obama did on guns

Republican candidates accused President Obama on Thursday of "undermining the 2nd Amendment" and wanting to "confiscate every gun in America." Chris Christie called him a "petulant child" for using his authority to try to limit gun violence.

Obama's executive actions this month on guns, though, fell far short of his own goals of requiring background checks on every potential gun buyer or ending the so-called gun show loophole.

Here is what Obama did instead:

Issued new guidelines on what constitutes a private gun sale.

Announced a campaign to educate gun sellers on licensing requirements.

Announced plans to hire more investigators to expedite background checks

As for the candidates' excoriations? Well, in Washington, such outrage is a familiar refrain.

Florida Sen. Marco Rubio has accused Chris Christie of making a personal donation to Planned Parenthood, but the New Jersey governor denied it in Thursday’s Republican presidential debate in South Carolina.

Christie has acknowledged shifting from an abortion rights supporter to being antiabortion in 1995 after hearing the prenatal heartbeat of his daughter when his wife was 13 weeks pregnant.

“I never gave money to Planned Parenthood,” Christie said Thursday.

Whether he had personally given money to Planned Parenthood before that is a matter of dispute.

During his 1994 campaign for a local office, Morris County freeholder, Christie told the Newark Star-Ledger: “I support Planned Parenthood privately with my personal contribution and that should be the goal of any such agency, to find private donations. It’s also no secret that I am pro-choice.”

The context? A public debate over whether Morris County should restore its annual donation to a local Planned Parenthood chapter.

Christie blamed the newspaper for the confusion, though he did little to resolve it.

“Listen, this is a quote from 21 years ago,” Christie told the Washington Post this week. “I’m convinced it was a misquote. Understand what was going on. In 1994-95, I was fighting against county funding of Planned Parenthood even though I was pro-choice.”

Trump brushes off Nikki Haley's criticism

GOP front-runner Donald Trump said during the debate that he was not offended by South Carolina Gov. Nikki Haley’s denunciation of him during her response to President Obama’s State of the Union address this week.

“I am a friend of hers,” Trump said, noting that he met with the Republican governor this afternoon before the debate. “Wherever you are sitting, Nikki, I am a friend.”

Haley’s speech – the official GOP response to Obama – illustrated the fault line in the Republican Party that is driving the dynamics of this year’s presidential campaign.

“During anxious times, it can be tempting to follow the siren call of the angriest voices. We must resist that temptation,” Haley said. "No one who is willing to work hard, abide by our laws, and love our traditions should ever feel unwelcome in this country.”

Haley did not mention Trump by name, but later said she was referring to him, among others, in those remarks.

Her response was praised by the GOP leadership and some Democrats. Trump, though, in the immediate aftermath called Haley soft on immigration, and other conservative Republicans bashed her. Conservative commentator Ann Coulter said Haley ought to be deported. (Haley is the American-born daughter of Indian immigrants.)

During the debate, Trump stood by his anger and said it is justified.

“I’m very angry because our country is being run horribly, and I will gladly accept the mantle of anger,” Trump said. “Our military is a disaster. Our healthcare is a horror show. Obamacare – we’re going to repeal it or replace it. We have no borders. Our vets are being treated horribly. Illegal immigration is beyond belief. Our country is being run by incompetent people. So, yes, I am angry.”

Before and since her speech, Haley’s name has been floated as a potential vice presidential pick.

Haley was viewed as a rising Republican star when she was elected governor in 2010, but her luster faded amid battles with her state’s Legislature. Her popularity in South Carolina increased as the economy improved, and the moment that pushed her into the national spotlight was her handling of the June mass shooting at a historic African American church in Charleston, and the ensuing decision to take down the Confederate flag on the State House grounds.

If Haley were put on the ticket, as a minority and a woman, she would be a representation of the groups of voters that the GOP recognizes as crucial in its efforts to retake the White House.

Though he was born in Canada, Ted Cruz is almost certainly eligible to be president

(Rainier Ehrhardt / Associated Press)

Whether Canadian-born Ted Cruz is eligible for the presidency has repeatedly come up on the campaign trail, thanks chiefly to Donald Trump, who says the Republican Party could be put in a “very precarious” place if Cruz wins its nomination.

Cruz was ready for such an attack Thursday night. When asked by moderators about the issue, he cast it as a desperate move by Trump as his lead weakens. He noted that last fall, when Cruz was well behind Trump in the polls, Trump said the issue was settled.

“Since September, the Constitution hasn’t changed, but the poll numbers have," Cruz said to cheers.

After delivering a lecture on the legal question, Cruz pivoted back to Trump to note that some conspiracy theorists about presidential birthplaces -- the so-called birthers -- believe the law requires that both parents of a president be born in the U.S. Trump’s mother was a naturalized American born in Scotland.

That touched off the night's first hot exchange, with Trump defending himself and telling Cruz he can't "do that to the party" by allowing a lawsuit over his birth during an election.

The matter of presidential eligibility has been debated by political pundits and constitutional scholars, with most agreeing that Cruz is indeed eligible to hold the nation’s highest office despite the fact that he was born outside the U.S.

At issue is Article II of the Constitution, which states: “No Person except a natural born Citizen ... shall be eligible to the Office of President.”

Trump has suggested that Cruz, who was born in Calgary to a U.S.-born mother and Cuban-born father, is not a natural-born citizen. He has cited some constitutional law experts who say the narrowest interpretation of the law may forbid Cruz from being president.

But that is a minority opinion. Legal experts overwhelmingly agree that the question is settled as to whether a child born abroad to a U.S. parent is a citizen at birth.

If he were elected in November, Cruz would become the nation's first president born outside the United States. But he is not the first presidential candidate born elsewhere.

Sen. John McCain of Arizona, the GOP nominee in 2008, was born in the Panama Canal zone. Sen. Barry Goldwater, who ran for president in 1964, was born in the territory of Arizona before it became a state.

6:29 P.M.

I am very pleased to get a question this early on. I was going to ask you to wake me up when the time came.

Dr. Ben Carson, on getting a debate question before the first commercial break

6:23 P.M.

Trump on Syrian refugees

Cruz raises Iranian detention of American sailors to slash at Obama's priorities

Texas Sen. Ted Cruz kicked off Thursday's prime-time GOP debate by lashing out at President Obama for not mentioning in his State of the Union address the 10 American sailors who were briefly detained by Iran after they sailed into that country's territorial waters.

“Today, many of us picked up our newspapers and we were horrified to see the sight of 10 American sailors on their knees with their hands on their hands,” Cruz said. “In [Tuesday’s] State of the Union, President Obama didn’t so much as mention the 10 soldiers that had been captured by Iran.

“The good news is the next commander in chief is standing on this stage,” Cruz said, adding that if he was elected to the White House, “no serviceman or servicewoman will be forced to be on their knees, and any nation that captures our men and women will feel the full force and fury of the United States of America.”

Cruz aligned himself with other Republicans who have held up the brief detention of the U.S. sailors as proof of what they call Obama’s failed foreign policy.

But Democrats argue that the swift resolution – the sailors were released a day after their capture -- reflected the improved diplomatic relationship between the U.S. and Iran after the nuclear agreement the two nations and five others reached this summer. They compared it to the capture of British sailors in disputed waters in 2007; they were held for 13 days by Iran.

Secretary of State John F. Kerry negotiated the release with Iranian Foreign Minister Mohammad Javad Zarif. The two men had an existing relationship because of their work on the nuclear accord, which is expected to go into effect next week.

The sailors were manning two patrol boats that entered Iranian waters near a major Iranian naval base. Initial reports that one of the boats had a mechanical malfunction were later found to be untrue, and it remains unknown why the boats entered Iranian waters.